Merkel is asking the question that the British public and the anti and pro membership campaigns are asking as well. If one of the leading players in the EU is not sure what the UK's position is then this will hinder the renegotiation process.
So far Mr Cameron has not had to reveal his hand too much. But all the time he is telling the pro- campaign to hold back whilst the anti- campaign feels no such qualms then he will come under increasing pressure.
What was most noticeable from the Conservative Party conference was how interested members were in the EU debate and how much the leadership wanted to avoid talking about it.
2016 is the year when the issue will come to a head.
Angela Merkel is expected to push David Cameron to spell out his negotiating position on the European Union when the leaders meet on Friday, as the main campaign calling on the UK to leave Brussels launched.